Anc noise active control audio headset with prevention of the effects of a saturation of the feedback microphone signal

Abstract

The headset includes an active noise control, with an internal ANC microphone () placed inside the acoustic cavity () and delivering a signal including an acoustic noise component. A digital signal processor DSP () comprises a feedback ANC branch () applying a filtering transfer function (, H) to the signal delivered by the ANC microphone, and a mixer () for mixing the signal of the feedback branch with an audio signal to be reproduced (M). The headset comprises a movement sensor () mounted on one of the earphones. The DSP comprises an anti-saturation module () for analyzing concurrently i) the signal delivered by the internal microphone () and ii) the signal delivered by the movement sensor (), and verifying whether current characteristics of these signals fulfill or not a set of predetermined criteria. Upstream from the feedback ANC filter (), an anti-saturation filter (, H) is selectively switched as a function of the result of this verification. The filtering of an equalization branch (, H) of the signal to be reproduced (M) is also modified by a similar anti-saturation filter (, H).